109. Correctly measuring the productivity of service workers is complex. Consider, for example, postal workers: they are often said to be more productive if more letters are delivered per postal worker. But is this really true?What if more letters are lost or delayed per weoker at the same time that more are delivered? The objection implied above to the productivity measure described is based on doubts about the truth of which of the following statement?
B) the delivery of the letters is the primary activity of the postal service.
E) the number of letters delivered is relevant to measuring the productivity of postal workers.
为什么这题答案是B而不是E 我下的pdf这题没有官方解释 | 
